Details
| Original language | English |
|---|---|
| Qualification | Doctor of Engineering |
| Awarding Institution | |
| Supervised by |
|
| Thesis sponsors |
|
| Date of Award | 7 Aug 2023 |
| Place of Publication | Hannover |
| Publication status | Published - 2023 |
Abstract
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
Hannover, 2023. 341 p.
Research output: Thesis › Doctoral thesis
}
TY - BOOK
T1 - Applying temperature-sensitive electrical parameters to SiC power modules considering parasitic effects
AU - Herwig, Daniel
PY - 2023
Y1 - 2023
N2 - Temperature-sensitive electrical parameters (TSEPs) can be used to monitor the condition of unmodified power modules or to measure the virtual junction temperature of a semiconductor. The measurement of TSEPs on fast-switching wide-bandgap semiconductors poses new challenges with regard to the required measurement accuracy and the high EMI tolerance capability. Furthermore, TSEPs are affected by many parameters beside the virtual junction temperature or the degradation state of the module. These cross-dependencies can be separated into parameters that are typically measured during operation, e.g., the load current, and parasitic impacts that are unknown, or cannot be feasibly acquired. In this thesis, the application of TSEPs to fast-switching wide-bandgap silicon carbide (SiC) MOSFETs is studied, giving special consideration to parasitic impacts. Examples of these impacts are changes in the gate driver's temperature or instabilities in the gate driver's voltages. Parasitic impacts can lead to significant deviations in the virtual junction temperature determined. Several TSEPs are acquired simultaneously and combined to reduce the effects of these impacts on the TSEP-based temperature estimation. The TSEPs used are the on-state voltages of the switches and two switching times during turn-on. The suitability of artificial neural networks for combining and mapping multiple TSEPs to a single virtual junction temperature estimate is investigated and compared to physics-based approaches. A variety of detailed analytical models representing the on-state voltage and switching times during turn-on are investigated, including SiC-specific effects. The aim is to determine which level of model complexity is necessary to separate the temperature-dependent behavior from the current-dependent behavior of the considered TSEPs. Simultaneously, the analytical modeling identifies numerous possible parasitic impact factors which affect the measurement of TSEPs. Beside the theoretical aspects, TSEP measurement hardware for the on-state voltage and switching times of SiC MOSFETs is designed. This is used to acquire TSEP measurements in double-pulse experiments as well as during continuous PWM operation. Challenges arising from the short conduction phases at high switching frequencies and also from PWM-specific effects are studied and compensation concepts are presented. Detailed thermal models of the power module and test setup are created, together with a current model which determines the instantaneous current during turn-on from the scalar current sample provided by the inverter sensors. Finally, accelerated aging tests are conducted. Several power modules are power cycled until they reach their end of life. During the testing they are periodically analyzed with the TSEP measurement system. The test results verify that the TSEP measurement system is capable of detecting thermomechanical degradation mechanisms before the module reaches its end of life.
AB - Temperature-sensitive electrical parameters (TSEPs) can be used to monitor the condition of unmodified power modules or to measure the virtual junction temperature of a semiconductor. The measurement of TSEPs on fast-switching wide-bandgap semiconductors poses new challenges with regard to the required measurement accuracy and the high EMI tolerance capability. Furthermore, TSEPs are affected by many parameters beside the virtual junction temperature or the degradation state of the module. These cross-dependencies can be separated into parameters that are typically measured during operation, e.g., the load current, and parasitic impacts that are unknown, or cannot be feasibly acquired. In this thesis, the application of TSEPs to fast-switching wide-bandgap silicon carbide (SiC) MOSFETs is studied, giving special consideration to parasitic impacts. Examples of these impacts are changes in the gate driver's temperature or instabilities in the gate driver's voltages. Parasitic impacts can lead to significant deviations in the virtual junction temperature determined. Several TSEPs are acquired simultaneously and combined to reduce the effects of these impacts on the TSEP-based temperature estimation. The TSEPs used are the on-state voltages of the switches and two switching times during turn-on. The suitability of artificial neural networks for combining and mapping multiple TSEPs to a single virtual junction temperature estimate is investigated and compared to physics-based approaches. A variety of detailed analytical models representing the on-state voltage and switching times during turn-on are investigated, including SiC-specific effects. The aim is to determine which level of model complexity is necessary to separate the temperature-dependent behavior from the current-dependent behavior of the considered TSEPs. Simultaneously, the analytical modeling identifies numerous possible parasitic impact factors which affect the measurement of TSEPs. Beside the theoretical aspects, TSEP measurement hardware for the on-state voltage and switching times of SiC MOSFETs is designed. This is used to acquire TSEP measurements in double-pulse experiments as well as during continuous PWM operation. Challenges arising from the short conduction phases at high switching frequencies and also from PWM-specific effects are studied and compensation concepts are presented. Detailed thermal models of the power module and test setup are created, together with a current model which determines the instantaneous current during turn-on from the scalar current sample provided by the inverter sensors. Finally, accelerated aging tests are conducted. Several power modules are power cycled until they reach their end of life. During the testing they are periodically analyzed with the TSEP measurement system. The test results verify that the TSEP measurement system is capable of detecting thermomechanical degradation mechanisms before the module reaches its end of life.
U2 - 10.15488/15128
DO - 10.15488/15128
M3 - Doctoral thesis
CY - Hannover
ER -